The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.
A pair of images that are used for forming a three-dimensional image of a stereoscopic viewer needs to be aligned properly for comfortable viewing. Horizontal alignment is necessary so that the two eyes do not need to diverge in order to view the image. A small amount of convergence is desirable in the image.
Vertical alignment is necessary to avoid double vision. When there is double vision the three dimensional effect is lost. The simple but tedious method of achieving vertical alignment is to move each final image (e.g., each final print or screen image) relative to each other.
The inventor has determined that a better way to form a stereoscopic image is to align a pair of images when the pair of images is captured on an image-capturing device of a camera. Most cameras have a single image-capturing device, such as a film or an image sensor (e.g., a charge couple device can be an image sensor).
Since several components are assembled together, the build up of tolerance errors is unavoidable. Aligning the image on an image capturing device requires high precision since the captured images are usually enlarged for viewing. To maintain the alignment during the working life of the equipment, it is best that the components are not under any stress such as spring tension. Also, vibration and shock loads may upset the settings.
FIG. 1 shows a mount for mounting a mirror or prism, having mirrors (item 1), adjustment screws (item 2), and a spring (item 3). Similarly, FIG. 2 shows another mount for mounting a mirror or prism, having mirrors (item 1), adjustment screws (item 2).
With reference to FIG. 1, where mirrors (item 1) or prisms are used, in order to achieve the prefect alignment with no backlash, usually adjustment screws (item 2) are arranged to press, or work, against a spring (item 3) (backlash is the loss of motion between driving and driven elements due to clearance between parts). Alternatively, sometimes two adjustment screws (item 2) work against each other, see FIG. 2 in order to hold the screws in one position. Both methods, that is the mounts of both FIGS. 1 and 2, involve stress.
Also, the methods of FIGS. 1 and 2 allow adjustments in only one plane. Usually two different mirrors or prisms along the optical path will have to be adjusted separately to provide X and Y axis alignments (which may be referred to as horizontal and vertical alignment). The need to adjust two mirrors along the same optical path doubles the labor cost and doubles the chances of drift in the alignment with time or during use.
FIGS. 3 and 3A show a mounting arrangement with four mounting points (item 4), having height difference B (FIG. 3), plate (item 5), line ‘A’-‘A’ (FIG. 3A). FIGS. 3 and 3A show a mounting arrangement with 4 mounting points (item 4). If all four are slightly different in height, as shown at B (FIG. 3), due to a manufacturing error (for example), the plate (item 5) is bent when screwed down tightly, and consequently stress sets in along the lines ‘A’-‘A’ (FIG. 3A).